Barack Obama has won the Iowa caucuses. You’d have to have a heart of stone not to feel moved by this. An African-American man wins a closely fought campaign in a pivotal state. He beats two strong opponents, including the mighty Clinton machine. He does it in a system that favors rural voters. He does it by getting young voters to come out to the caucuses.

This is a huge moment. It’s one of those times when a movement that seemed ethereal and idealistic became a reality and took on political substance."